1. Field of the Invention
The present invention relates to an improvement in a sorting apparatus which is combined with an image forming apparatus to sort out recording mediums discharged from the image forming apparatus.
2. Description of the Prior Art
Generally a sorter 10 is used in combination with an image forming apparatus 1 as shown in FIG. 2. A transport section 18 in the sorter 10 carries sheets of paper 5 as recording mediums discharged from the image forming apparatus 1 successively to each of an array of bins 20 attached to the sorter 10 so that a specified number of recording sheets 5 are stacked in respective bins 20.
As shown in FIG. 2, the bins 20 attached to the sorter 10 are vertically arrayed at equal intervals and serially numbered from the top down on, with the top bin numbered as a first bin, the next bin as a second bin and so on until the bottom bin as an n-th bin. The recording sheets 5 are sorted out and carried to these bins, beginning with the first bin 20 and ending with the n-th bin 20.
In this kind of sorter 10, a desired number of recording sheets 5 to be sorted out is preset to a CPU 3 in the image forming apparatus 1. According to the control of the CPU 3, the sorter 10 successively performs an open-close operation on a series of gate members provided one to each bin 20 so that the recording paper 5 is carried along the surface of the gate member, which has closed a transport passage of the recording paper 5, into the associated bin 20.
A conventional drive mechanism for opening and closing the gate member consists, as shown in FIG. 8, of a gate member 21, a gate arm 21d attached to one end of the gate member, a solenoid 24 engaged with the gate arm 21d to pivot the gate member 21, and a switching element and wires to activate the solenoid 24.
As shown in FIG. 7, the recording sheets of paper 5 are carried by the transport section 18, which consists of a belt 14 wound on first paired rollers 12 and a second roller 13 and a group of third rollers 15 arranged on both sides of the belt 14.
When the recording paper 5 is fed along the surface of the gate member 21 for the first bin 20, that has closed the transport passage of the paper 5, into the first bin 20, a detecting section (not shown) sends to the CPU 3 of the image forming apparatus 1 a feedback signal representing that the paper 5 is completely placed in the first bin 20. The CPU 3 now activates the solenoid 24 for the first bin 20 to pivot the associated gate member 21 counterclockwise and thereby open the transport passage of the paper 5 and at the same time drives the solenoid 24 for the second bin 20 to pivot the associated gate member 21 clockwise.
The resultant closing of the transport passage for the recording sheet 5 by the gate member 21 associated with the second bin 20 permits the recording sheet 5 to be introduced along the surface of the gate member 21 into the second bin 20. In this way, the sorter 10 equipped with n bins successively operates the solenoids 24, starting with the one associated with the first bin 20 and ending with the one for the n-th bin 20, to rotate the corresponding gate members 21 and thereby repetitively open and close the recording paper transport passage. This series of operations is repeated a specified number of times to sort out and deliver into each of the bins a required number of sheets 5 which are copies obtained from different documents on the image forming apparatus. As for the n-th bin 20, which is the last bin, the associated gate member 21 is fixed to close the transport passage of the recording sheet 5, so that no solenoid 24 nor switching element is provided.
As mentioned above, the conventional drive mechanisms to open and close the gate members 21 to sort out the recording sheets 5 employ the solenoids 24 and switching elements.
For example, suppose one wants to make twenty copies from each of a plurality of documents with the recording sheets 5. A sorter 10 with twenty bins should be used. This sorter 10 requires 20 gate members 21 for the bins 20, and 19 solenoids 24, 19 switching elements and associated wiring to drive the gate members 21. Since many expensive solenoids 24 and switching elements as well as a large printed circuit card and complex wiring connecting these components must be assembled and installed, a number of manufacturing processes are required.
Because the drive mechanisms that open and close the gate members 21 to sort out the recording sheets 5 require expensive components and a number of manufacturing processes, the overall manufacturing cost of the sorter 10 necessarily increases.